A charged particle beam apparatus is widely used for length measurement or pattern inspection of a semiconductor wafer. In recent years, in order to inspect a deep groove or a deep hole in a semiconductor process with a three-dimensional structure, there has been a demand for a high voltage of an acceleration voltage for generating and accelerating a charged particle beam in the charged particle beam apparatus. Further, in order to achieve high resolution of a measurement image, there has been a demand for a ripple reduction of a high-voltage power supply that generates various types of high voltages including the acceleration voltage.
Additionally, since the high-voltage power supply handles several kilovolts to tens of kilovolts, it is necessary to detect an overcurrent flow due to a high-voltage discharge or a component failure with high accuracy and to stop an operation safely. In addition, since the charged particle beam is generated from a load current that is supplied from the high-voltage power supply, there has been a demand for a high-voltage power supply that is capable of detecting the load current with high accuracy in order to obtain the measurement image having the high resolution.
PTL 1 discloses a high-voltage power supply for an electron gun of a charged particle beam apparatus, which avoids false detection and detects an output current with accuracy by grounding a shield of a transformer to a potential portion that is generated by a shunt resistor for overcurrent detection.
In addition, NPTL 1 discloses a charged particle beam apparatus including means for detecting a defect with high accuracy by detecting an absorption current.